TY - JOUR
T1 - Does pre-emptive analgesia work, and why?
AU - Niv, David
AU - Devor, Marshall
PY - 1996
Y1 - 1996
N2 - Pre-emptive analgesia probably has little role to play in surgery currently undertaken using local or regional nerve blocks. For surgery performed under general anaesthesia, many of the second tier clinical trials found no difference in postsurgical pain when regional analgesia was provided just before versus just after surgery. Others found a significant, but modest, effect of pre-emptive analgesia. Part of the difference may lie in the use of supplemental analgesics and the choice of general anesthetic protocol. Indeed, it seems that much of the benefit that pre-emptive analgesia can provide may already be exploited in the current protocols for general anaesthesia, which usually include opioids and other analgesics together with nitrous oxide. Further research is needed to determine whether the optimization of protocols can squeeze out whatever residuum remains. The intentional avoidance of supplemental opioids in the positive studies of Katz et al., Richmond et al. and Collis et al. was probably instrumental in demonstrating an effect. In special situations in which supplemental analgesics, and especially opioids, need to be avoided, pre-emptive analgesia may be of practical interest. However, predictions of a coming revolution in postoperative pain management through pre-emptive analgesia appear to have been overly optimistic. The possibility that triggering central sensitization in the clinical setting is practically unavoidable (the Hydra problem), and the obverse possibility that current anesthetic practice already maximally pre-empts central sensitization, does not address the contribution that central sensitization may make to pain sensation in the absence of drugs. Pain of peripheral origin is clearly amplified by central sensitization, and this amplification appears to be maintained for as long as the peripheral source is present. Therefore, the development of techniques for blocking the central sensitization process itself (e.g. NMDA channel antagonists) may in the future provide a new tool for the management of postoperative and other pain states. The ultimate importance of this approach, however, depends on the degree of amplification caused by central sensitization. This parameter remains unknown.
AB - Pre-emptive analgesia probably has little role to play in surgery currently undertaken using local or regional nerve blocks. For surgery performed under general anaesthesia, many of the second tier clinical trials found no difference in postsurgical pain when regional analgesia was provided just before versus just after surgery. Others found a significant, but modest, effect of pre-emptive analgesia. Part of the difference may lie in the use of supplemental analgesics and the choice of general anesthetic protocol. Indeed, it seems that much of the benefit that pre-emptive analgesia can provide may already be exploited in the current protocols for general anaesthesia, which usually include opioids and other analgesics together with nitrous oxide. Further research is needed to determine whether the optimization of protocols can squeeze out whatever residuum remains. The intentional avoidance of supplemental opioids in the positive studies of Katz et al., Richmond et al. and Collis et al. was probably instrumental in demonstrating an effect. In special situations in which supplemental analgesics, and especially opioids, need to be avoided, pre-emptive analgesia may be of practical interest. However, predictions of a coming revolution in postoperative pain management through pre-emptive analgesia appear to have been overly optimistic. The possibility that triggering central sensitization in the clinical setting is practically unavoidable (the Hydra problem), and the obverse possibility that current anesthetic practice already maximally pre-empts central sensitization, does not address the contribution that central sensitization may make to pain sensation in the absence of drugs. Pain of peripheral origin is clearly amplified by central sensitization, and this amplification appears to be maintained for as long as the peripheral source is present. Therefore, the development of techniques for blocking the central sensitization process itself (e.g. NMDA channel antagonists) may in the future provide a new tool for the management of postoperative and other pain states. The ultimate importance of this approach, however, depends on the degree of amplification caused by central sensitization. This parameter remains unknown.
UR - http://www.scopus.com/inward/record.url?scp=0029761463&partnerID=8YFLogxK
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AN - SCOPUS:0029761463
SN - 0968-1302
VL - 3
SP - 79
EP - 90
JO - Pain Reviews
JF - Pain Reviews
IS - 2
ER -